The present application claims priority from German patent application no. 19959703.0, entitled xe2x80x9cTaktilsensorxe2x80x9d (translation is xe2x80x9cTactile Sensorxe2x80x9d) listing inventors Bjoem Magnussen and Cyril Valfort, and filed on Dec. 10, 1999.
Various position or pressure sensing input devices using tactile sensors have been previously developed. However, these conventional approaches often have been complex, difficult or expensive to manufacture, and/or had limited performance, especially for large area input device applications.
One approach has been to provide a touch surface that is an elastic, air-permeable sensor material sealed by an airtight cover to provide an airtight region, wherein atmospheric pressure sensors are installed. A pressure contact by an object toward the touch surface changes the internal pressure within the airtight region, such that the atmospheric pressure sensors can measure the pressure change associated with the force of the contact. However, this approach cannot determine the position of the contact.
Another approach is to have a touch surface covered with a sensitive thin material that can detect a contact using capacitive or piezo-electric measurement principles. Being fairly expensive and complicated to manufacture, this approach is typically used for higher-end position sensing devices covering a small area, such as for a touchpad input for portable computers.
Yet another approach is to use two resistive or conductive materials in the touch surface in order to measure a contact using resistive measurement principles. For example, a foil print sensor that includes a conductive plastic material mounted on an interdigital electrode comb structure can provide a resistive measurement between proximate electrodes of the comb structure, as an increased pressure from a contact on the touch surface results in a decreasing resistance (between these particular electrodes) that is measured to provide a location of the contact. Foil print sensors are, however, expensive to produce. Other examples include digitizing input tablets proposed in U.S. Pat. No. 3,959,585 issued to Mattes et al., in U.S. Pat. No. 4,455,450 issued to Margolin, and in U.S. Pat. No. 4,517,546 issued to Kakuhashil. In the types of digitizing tablets discussed by Mattes et al. and by Margolin, a first resistive sheet having x-direction measuring electrodes and a second resistive sheet having y-direction measuring electrodes have a separation maintained between each other by a pressurized air gap or other generally non-conducting material. When a contact is made onto the touch surface, the resistive sheets come into closer contact with each other to result in a decreasing resistance that can be measured in the x and y directions to determine the location of the contact. In the type of digitizing tablet discussed by Kakuhashi et al., a first multi-layer resistive sheet having x-direction measuring electrodes and a second multi-layer resistive sheet having y-direction measuring electrodes sandwich an elastic, pressure-sensitive conductive sheet. When a contact is made onto the touch surface, the resistive sheets are contacted electrically together through the conductive sheet. Involving various steps and technical processes to provide the multi-layer resistive sheets, film electrodes, and insulative bonded layers discussed therein, the construction of such a device is complicated and expensive. For larger area input devices, the processes involved in construction become unrealistic, as well as costs becoming excessive. Even with larger area input devices such as an electronic whiteboard using a conventional resistive membrane technology such as discussed in U.S. Pat. No. 5,790,114 issued to Geaghan et al. and assigned to Microtouch Systems, Inc., the need to sustain the gap between the resistive sheets of the resistive membrane technology can result in a complicated mechanical apparatus, such as described in U.S. Pat. No. 5,838,309 issued to Robsky et al. and also assigned to Microtouch Systems, Inc. However, providing a consistent gap appears to be crucial for obtaining consistent measurements for these types of large area input devices.
In addition to the various disadvantages to the conventional approaches discussed above, many large area input devices also have required dedicated, expensive computer and video equipment in order to provide broader communication of the input information beyond the one room where such a device may be located. For example, as discussed in U.S. Pat. No. 5,790,114 mentioned above, the electronic whiteboard system has a direct connection to a dedicated computer with monitor to view the input information written on the whiteboard. Other electronic whiteboard systems further require expensive optical scanner equipment in addition to a dedicated computer with monitor, as illustrated in U.S. Pat. No. 6,009,240 issued to Eguchi et al. Besides being expensive and unaffordable to many potential electronic whiteboard purchasers, this extra computer and video equipment used with a particular electronic whiteboard takes up physicals space and can be bulky to move if this type of equipment is a limited resource and is desired to be used with another electronic whiteboard in a different room.
It is seen from the above that an alternative approach to larger area electronic whiteboards that provide consistent measurements for determining contact location in an economic and simplified manufacturing process is desirable. Further, it is desirable to have an economic, less bulky approach to broadly utilizing an electronic whiteboard for wide communication.
According to a specific embodiment, the present invention provides an electronic whiteboard that includes a foam sensor with a plurality of electrodes, and an erasable writing surface disposed on top of the foam sensor. The erasable writing surface has an input area. The electronic whiteboard also includes circuitry, coupled to the electrodes, that measures pressure and position data of a contact made to the input area of the writing surface.
In accordance with another specific embodiment, the present invention provides an electronic whiteboard network appliance. The electronic whiteboard network appliance includes a sensor with a plurality of electrodes; an erasable writing surface disposed on top of the sensor that has an input area to which a contact having pressure and position data may be made; an audio input such that audio data is synchronized with said pressure and position data; circuitry coupled to the electrodes and audio input; and a network interface. The circuitry measures the pressure and position data of the contact, and synchronizes the audio data to the measured pressure and position data. The network interface is coupled to the circuitry and transmits the measured pressure and position data with synchronized audio data within network packets to a network for use at a network device.
In accordance with another specific embodiment, the present invention provides an electronic whiteboard meeting system over a network. The system includes an electronic whiteboard encoding system having a network interface, a network server connected to the network, and a plurality of devices logically connected to the network. The electronic whiteboard encoding system measures position data from contacts made during an electronic whiteboard meeting to a writing surface of the electronic whiteboard encoding system, and transmits the position data in network packets via the network interface to the network. The network server is installed with serve software capable of reading and storing the position data for transmission over the network. At least one device of the plurality of devices is provided with client software capable of accessing and translating the position data from the network server into a representation of the electronic whiteboard meeting.
These and other various specific embodiments of the present invention as well as their features and advantages are described in more detail in conjunction with the following drawings.